Alkyl alpha-fluoroacetoxy acrylates, and polymers thereof



Patented Sept. 23, 1952 ALKYL a-FLUOROACETOXY ACRYLATES,

AND POLYMERS THEREOF f Joseph B. Dickey and Theodore E. Stanin, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation ofNew Jersey No Drawing. Application August 11, 1950, 1

' Serial No. 179,002

12 Claims. (Cl. 260 -783) 7 U This invention relates to alkyl alpha-fluoroacetoxy acrylates, to polymers thereof, and to a process for their preparation.

This application is a continuation-in-part of ourcopending application Serial Number 654,523, filed March 14, 1946 (now U. S. Patent 2,525,530, dated October 10, 1950).

The new compounds of the invention are rep resented by the following general structural formula:

wherein R represents an alkyl group containing from lto 4 carbon atoms (e. g. methyl, ethyl, propyl, isopropyl, n-butyl, etc. groups) and X represents an atom of hydrogen or an atom of fluorine. The above-defined compounds are valuableintermediates for the preparation of other useful organic compounds, but especially valuable for the preparation of resinous polymers which are characterized by being less flammable and more stable to heat and water than similar acrylates containing no fluoromethyl group. The polymers are useful for the preparation of coating and impregnating compositions, sheets, threads, fibers, etc., and are also moldable to stable forms and shaped objects which are readily workable by mechanical means to desired finished products.

It is, accordingly,- an object of the invention to provide new fluorine containing compounds, and resinous polymers thereof. is to provide a process for preparing the same. Other objects will become apparent hereinafter.

In accordance with the invention, we prepare the new monomeric alkyl alpha-fluoroacetoxy acrylates by reacting a-difiuoroacetoxyor atrifluoroacetoxy-p-chloropropionitrile with dry hydrogen chloride in the presence of an alcohol (e. g. methanol, ethanol, propanol, butanol, etc.), hydrolyzing the iminoether obtained in aqueous solution, separating the alkyl a-difluoroacetoxyor alkyl a-trifluoroacetoxy-s-chloropropionate and reacting it with a tertiary organic amine (e. g. a trialkylamine such as triethylamine, tributylamine, etc., pyridine, quinoline, dimethylaniline, etc.) to give the desired alkyl a-difiuoroacetoxyor alkyl 'a-trifluoroacetoxy acrylate. The starting intermediates. adifluoroacetoxyand a-trifluoroacetoxy-p-chloropropionitriles can be readily prepared by est'erifying d-hydroxy-p- Another object chloropropionitrile with difluoroacetic w fluoroacetic anhydrides, respectivelyr jThe new monomeric compounds'can also be prepared'jby starting with an alkyl ester, for example, an alkyl a hydroxy- 3-chloropropionate can berefacted with difluoroacetic or trifiuoroacetidan hydride, followed by splitting off hydrogen chlo ride with one or more of the mentioned tertiary organic amines.

The polymerization of the new compounds'of the inventionJalone or conjointly with each other or with one or more other unsaturated organic compounds is advantageously carried out in the presence of a polymerization catalyst.;" Peroxide-- polymerizationcatalysts which are soluble in the monomers or in solvent mediums for the polymerization can be employed, e. g.; organic per oxides such as benzoyl peroxide, acetyl peroxide, lauroyl peroxide, tertiaryflbutyl hydroperoxide, etc. Water soluble inorganic peroxides can also be used, e. g. hydrogen peroxide, ammonium per sulfate, potassium persulfate, sodium persulfate, persulfuric acid, sodium perborate', the water soluble salts of percarbonic acid, the water-'solu ble salts of perphosphoric acid, the water solu ble salts of sulfo-per-acid (Caros acid). Boron trifluoride is also an effective polymerization catalyst. Mixtures of the catalysts can be employed. The amount of catalyst employed can advantageously be from 0.1 to 1% by weight of the monomersto be polymerized.

The polymerizations can be carried out in bulk (mass) in solvents or in heterogenous dis persion where the monomer or mixture'ofmonomers is dispersed in a nonsolvent for the monomers, the particles of dispersed monomers being small (emulsion) or relatively v large (b'ead *or granular). In both bulk and solvent pOIYmBIlZQtj tions, the organic peroxide catalysts are advan tageously employed. Suitable solvents-include acetone, l l-dioxane, methanol, ethanol, 'I 'I l1X- tures of these solvents with minor portions of water, benzene, etc. Mixtures of solventscanbe employed. I

For emulsion polymerization any nonsolvent for the monomer or the mixture of monomers can be employed, Water being especiallyadvanftageous. The monomer or mixture of monomers:

can be advantageously emulsified in water using emulsifying agents such as salts of higher fatty acids, e. g. sodium or potassium stearate, palmitate, etc. or ordinary soaps, saltslof higher fatty alcohol sulfates, e. g. sodium orpotassium lauryl sulfate, sodiumor potassium"di(2jethylhexyl) sulph'osuccinate, sodiumv or p'otass lu nii cetyl sulfate, sodium or potassium stearyl sulfate, etc., salts of aromatic sulfonic acids, e. g., sodium or potassium salts of alkylnaphthalene sulfonic acids, etc, higher molecular weight quaternary ammonium salts, e. g., dimethyl benzylphenyl ammonium'chloride, quaternary ammonium salts containing the radicals 0151-131 and CrIHss, etc. Mixtures of emulsifying agents can be employed. For bead or granular polymerization, relatively poor dispersing agents such as starch, methylated starch, gum arabic, polyvinyl alcohol, partly hydrolyzed polyvinyl acetate, gelatin, sodium glycolate, etc. can be employed. Mixtures ofthese dispersing agents can also be used. In the above polymerizations wherein the monomer or mixture of monomers is dispersed in a nonsolvent, the dispersion can be facilitated by stirring, shaking or tumbling the polymerization mixture. Heat accelerates all the polymerizations, a temperature of from 30 to 120 C. tor a period of i'rdm'iip minutes to as much as'severalda'yspr more'belng advantageous.

copolymers of'the invention'can contain variable 'amouiits of each como'nomer and are obtained with starting polymerization mixtures containing from to 95 parts by weight of the new compounds of the inventionand from 95 to 5 partsby weight of one or more other unsaturated organic compounds. The resinous .copolymers'obtained have'found to be substantially of the 'same'p'roportions as the starting mixtures o fgcomonomers. Suitable other unsaturates for copclymerizing' with thenew' compounds of'the invention include vinyl 'carboxylic acid esters such asvi'nyl acetate, vinyl pro'pionate', vinyl benzoate, eta, alkyl esters'of acrylic and methacrylic acids such as methyl acrylate, ethyl acrylate,'butyl -acrylate, "methyl methacrylate, etc, unsaturated nitriles' such as acrylonitrile, methacrylonitrile, etc; vinyl hydrocarbons such as styrene, a-methylstyrene, vinylchlori'de, etc. and similar ethylenically unsaturated organic compounds.

The following examples 'will' serve to illustrate further our new 'unsaturates, polymers thereof, and 'the marinerof preparing the same.

Prpdrationof ethyl a-trifluoroacetowy e-chloro- I -propionate (:q) 23: gfof tri fl uoroacetic anhyd'ride' were slowly added to a cooled solution of 1 5 g. of ethyl -hydroxy s-chloropropionate in 100- cc.

of diethyl'; ether. The temperature" was maintained at'll" Cfduring the'addition'of'the'triiljuoroacetic anhydride'bycooling inan ice' salt bath. After the addition was completed, the reaction'mixture wasfhated to gentle reiiu x for a period of onei'hour. Fractionation of the reaction mixture gave a 92% yield of ethyl d-triflfioroacetoxy-fi chloropropionate,--' B. P. 72 741 Q./8-.-9 mm. pressure. I

By substituting an equivalent'amount' of'difluoroacetic anhydride' for the 'trifiuoroacetic anhydride inthe above example, there is-obtained the corresponding diiluoro compound, ethyl v. difiuoroacetoxy [5' chloropropionate. Also by replacing the ethyl a hydroxy-p-chloropropi'onate in the above example with an equivalent amount of other alkyl esters such as methyl ahydroxy-fi chloropropionate, butyl c-hydroxyg chloropropionate, etc the corresponding alkyl o.-ldifluoroacetoxyand alkyl a-trifiuoroacetoxyfll-chloropropionate, etc., are obtained.

(b) 4 g. of dry hydrogen chloride were slowly bubbled'into 17 g'. ofc trifiuoroacetoxyafl-chloroa propionitrile dissolved'in 50 cc. of dlethyl ether '4 containing 5 g. of anhydrous ethanol. The reaction mixture was allowed to stand for several hours after the addition of the hydrogen chloride was completed. The iminoether hydrochloride precipitated from solution. There were then added 75 cc. of water to the reaction mixture which hydrolyzed the iminoether to ethyl c-trifluoroacetoxy p chloropropionate. In place of the ethanol in the above example, there can be substituted an equivalent amount of other monohydric saturated aliphatic alcohols containing from 1 to 4 carbon atoms, to give the corresponding esters. For example, methanol gives methyl a-trifiuoroaceto'xy 5 chloropropionate, n-propanol gives n-propyl-a-trifiuoroacetoxy-fl-chloro- 'propionate and n-butanol gives n-butyl-a-trifluo- Y roacetoxy-B-chloropropionate.

Example 1.Ethyl e-trifluoroacetomy acrylate Example 2.n-Butyl a-trifluo'roacetoxy acrylate 27 g. of bu'tyl' a triliuoroacetoxyp-chloropropionate, B. P.- 104-406" C ./l5 mmrpressure, and 13 g; of quinoline' were added to -100cc.- ofbenzene. The reaction mixturewas refluxed-fora period of 20"hours. The-benzene solution was then washed with water and dilute hydrochloric acid, and dried over anhydrous'sodiumcarbonate. Fractionation of the'benz'enesolution-gave 84% yield of bu'tyl a'-t'rifluoroacet'oxyacrylate, B. P. 67-69" C./8-9mm.'pressure.

Example 3.Methyl e-tr z'fluoroacetoxyacrylate 24 g. of methyl a-triflucroacetoxy-e chloropropionate and 13 g. of quinoline were-added'to 100 cc. of "benzene. Thereactionmixture was refluxed for 15 hours. The benzene solution- -was washed with water and dilute hydrochloric acid,

v and dried overanhyclrous"potassium"corbonate.

Fractionation of the benzene solution "gave 89% yield of methyl a-trifluoroacetoxy'acrylatej B". P. 52-54 C./19'-20mm-. pressure. I

Example 4.'Ethyl a-difluoroacetoxy acrylate 23 g. of ethyl a-difiuoroacetoxy-fi-chloropropionate and 13- g. of quinoline'were addedto lOO cc. ofbenzene and the mixture-refluxed fora period of 12 hours. The-mixture --wasthen washed with water anddilute hydrochloric acid, and dried over anhydrous sodium --carbonate. Fractionation of the dried benzene solution-gave. anexcellent yield of ethyl u-difluoroacetoxy acrylate, B; P. 46-48" C./8-9 mm. pressure.

Example 5;'-n-Butyl-a-difluoroacetomy acrylate 6 g. of nbutyl a-difiuoroacetoxy-fl chloropropionate'and13 g. of quinoline were added tolOOI cc. of benzene. 'The'react'ion mixture wasree fluxed' for 20 hours. The niixturewas then washed with room' temperature water and dilutej hydrochloric acid,and dried over'anhyd'r'ou's sov:dium I carbonate.

carbonate;

Onfractionation of the dried benzene solution, there were obtained a good yield of n-butyl a-difiuoroacetoxy acrylate, B. P. 69-71 'C./ 8"9= mrn. pressure.

Example G-Methyl"a-difluomacetoxy acrylat'e 24 g. of methyl a-difluoroacetoxy-p-chloropropionate and 8 g. of pyridine were added to 100 Example 7.Poly butyl a-trz'fluoroacetomy acrylate 20 g. of butyl d-trifluoroacetoxy acrylate and 0.1 g. of benzoyl peroxide were placed in a sealed glass tube and heated in a water bath at 60 C. for a period of 24 hours. A clear, hard polymer which was soluble in acetone was obtained.

In place of the butyl a-trifiuoroacetoxy acrylate in the above examplathere can be substituted a like amount of methyl a-trifluoroacetoxy acrylate, ethyl a-trifluoroacetoxy acrylate or propyl atrifluoroacetoxy acrylate to give similar acetone soluble, clear, hard, resinous homopolymers. All of the polymers of this example were excellent molding materials.

Example 8.-Polymethyl a-difluoroacetoxy acrylate 30 g. of methyl a-difiuoroacetoxy acrylate were added to 100 cc. of distilled water in which were dissolved 3 g. of a sodium salt of a sulfonated hydrocarbon and 2 g. of soap flakes. To the above emulsion, there were added 0.3 g. of ammonium persulfate and 0.3 g. of sodium bisulfite. After agitating the emulsion at 50 C. for a period of 24 hours, it was poured into 300 cc. of saturated sodium chloride solution. The coagulated resinous polymer was washed with water and dried. It was soluble in acetone and 1,4-dioxane and readily moldable to clear, hard objects.

In place of the methyl a-difiuoroacetoxy acrylate in the above example, there can be substituted a like amount of ethyl a-difluoroacetoxy acrylate, propyl a-difluoroacetoxy acrylate or butyl a-difiuoroacetoxy acrylate to give similar acetone-soluble and 1,4-dioxane-so1ub1e, clear, hard, resinous homopolymers. All of these gave excellent results in molding compositions.

Example 9.Copolymer of methyl a-trifluoroacetoxy acrylate and ethyl a-trifluorcacetoxy acrylate 5 g. of ethyl a-trifluoroacetoxy acrylate, 10 g. of methyl a-trifiuoroacetoxy acrylate and 0.1 g. of benzoyl peroxide were placed in a sealed glass tube under an atmosphere of nitrogen, and the tube placed in a constant temperature both maintained at 50 C. After 16 hours, a hard, clear, resinous copolymer was obtained. It was soluble in acetone.

Example 10.Coplymer of ethyl a-triflaoroacetomy acrylate and methyl methacrylate g. of ethyl a-trifluoroacetoxy acrylate, 12 g. of methyl methacrylate and 0.09 g. of benzoyl peroxide were placed in a sealed glass tube under an atmosphere of nitrogen, and placed in a constant temperature water bath at 50 C. for a period of 20 hours. A clear, colorless, hard copolymeric resin was formed. v.tTheyresin ,was solublein acetone; 1.

Example 11.-- Copolymer of methylf trifluofov v aceto-ry'acrylateand' styrene' s-Y m :escala esarise;

of styrene and:0.08 g. of .benzoyl .peroxidewere p a d in a, seal d am ou e 11 F1 n tmosphere of nitrogen. The ampoulewas placed ina. con stant temperature bath maintainedat 50, 'C. After three days, ahard, clear, copolymer icresin had formed. .jIfhe polymer was solublein; acet e a d -1 ne -.It was e sigel eetrm terial for molding purposes.

Example 12.-C'opoly1ner of methyl a-trifluoroacetozcy acrylate and'aerylonitrz'le 5 g. of methyl a-trifluoroacetoxy acrylate, 10 g.

of acrylonitrile, 1 g. of potassium laurate, 0.1 g.

of potassium persulfate and 0.1 g. of sodium bisulfite were added to 50 cc. of water. The mixture was then tumbled in a Water bath at 40 C. for a period of 6 hours. The resulting copolymer was filtered, washed with water, and dried. The copolymer was soluble in acetone and contained by analysis 32% of methyl a-trifiuoroacetoxy acrylate groups, the remainder being acrylonitrile groups. It was spinnable from its solutions to give high quality yarn by a dry spinning method. Proceeding as shown in the foregoing examples, other resinous copolymers can be prepared, for example, from monomeric mixtures containing 5%, 15%, 25%, 45%, 55%, 75% or by weight of at least one of the new alkyl fluoroacetoxy acrylates of the invention, the remaining polymerizable monomers in each case being, for example, vinyl acetate, vinyl chloride, methyl acrylate, methyl methacrylate, acrylonitrile or similar unsaturates hereinbefore mentioned.

All of the polymers of the invention can be dissolved in one or more organic solvents, for example, in acetone, 1,4-dioxane, etc. to form solutions or dopes which can be extruded to filaments, coated to continuous sheets or applied as impregnating agents to paper and textile materials,

The copolymers with acrylonitrile are especially useful for preparing filaments which can be spun to yarn. The polymers of the invention can also be molded with or without plasticizers, fillers, coloring matter, etc., by means of extrusion, injection or compression methods into shaped objects.

What we claim is:

1. A compound having the following general structural formula: 

7. A POLYMER OF A COMPOUND HAVING THE FOLLOWING GENERAL STRUCTURAL FORMULA: 